Fix AngularJS from loading twice error on Rails 4

If you’re running a Rails 4.x app with AngularJS, and you’re getting
increasingly frustrated with receiving “AngularJS loaded twice” errors and you
can’t seem to figure out what went wrong, perhaps you might want to make sure
you do two things first:

First, remove Turbolinks Gem

Remove require ‘turbolinks’ from your application.js

It is not apparent at first but turbolinks inject its own form of javascript
into your views and when run, it will actually overwrite your normal angular
behavior.

I ran into this issue when routing to an angular page through ngRoute and than
hitting the back() button on my browser.

Turbolinks somehow intercepted it and cause angularJS to load twice causing the
controller function to not display the correct view in ng-view.

Hope this helps!

Extra Tip

Make sure that for all the templates in your routing controller, you remove
any instance of ng-controller in it as routeProvider would already
initialize the controller.

ie.

$routeProvider.when('/movies/:id', {
  templateUrl: 'movies/show.html',
  controller: 'moviesDisplayCtrl'
});

Make sure that in your movies/show.html, it doesn’t have the following in
it.

<div ng-controller="moviesDisplayCtrl">
</div>

This would also sometimes cause the double-loading error.